To improve the strength, deformation and durability of coral aggregates concrete (CAC), two strengthening methods of coral coarse aggregate (CCA) were proposed, i.e., cement paste coated CCA and cement dry-powder coated CCA. The strengthened coral aggregate concrete (SCAC) was prepared by strengthened CCA. The influences of the cement-coarse aggregate ratio (c/ca) of cement dry-powder and the water-cement ratio (w/c) of cement paste on the microstructure of strengthened CCA and the properties of SCAC were studied by macroscopic and microscopic mechanisms investigations. In general, the cracks propagation of SCAC was effectively inhibited and the failure of specimen became slow, owing to the improved microstructure of CCA, the dense aggregates coating and the high-strength composite CCA caused by strengthening cementitious materials. Compared with strength of CAC, that of SCAC was significantly enhanced and an 18.54% increase was obtained. Furthermore, the curvature of the stress-strain curve of SCAC increased and the decline of curve was gentle, causing the peak strain, ductility and energy dissipation of SCAC were 14.87%, 11.19% and 56.56%, greater than those of plain CAC, respectively. The deformability and energy dissipation capacity of SCAC were greatly improved. Based on the digital image correlation method, the deformation field distribution and damage process of SCAC were systematically studied to obtain its mechanism. Finally, an analytical stress-strain model of SCAC considering the effects of the strengthening variables was established, which would provide the basis for the practical application of SCAC structure.